Insulating Existing Concrete Flat Roof

Insulation material is placed on top of the roof rather than in between the ceiling and the decking.

Insulating existing concrete flat roof.

I ve built a timber frame to support a new plasterboard ceiling below the existing one. There are many different types and installation methods out there along with a lot misinformation about which products offer the greatest energy savings. Gable roofs hip roofs intersecting roofs butterfly roofs mansard. Green roofs a green sedum or grass roof can also be put onto a flat roof provided it can take the weight.

Roofing insulation is one of the most important and misunderstood building components. This method eliminates the need for ventilation and the risk of condensation whilst providing superior thermal performance to cold deck. Both these variants require different approaches to insulation which will be covered in this guide. Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation.

The insulation is below the deck but above the plasterboard. This is then covered with a further weatherproofing layer. I want to insulate below a flat roof without removing the existing ceiling. How to insulate a flat roof.

To insulate a flat roof with a concrete deck we recommend a warm deck construction method where the vapour control layer is sandwiched between the concrete deck and a layer of rigid pir insulation boards. To produce a hot roof rigid insulation is fitted outside above the weatherproofing. Insulation is placed in between the joists underneath the roof surface above. With an inverted warm roof construction put ballast usually graded pebbles or concrete paving slabs on top of the insulation in order to keep the insulation down in the event of wind.

There is only a small gap between this ceiling and a concrete roof cold roof felt covered. With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same. This is used for refurbishment e g. Here we share the most common mistakes people make when installing flat roofing insulation.

Cold roof systems are highly inadvisable as insulation from the inside will inevitably lead to the formation of condensation. The existing ceiling is sound but provides no insulation. A cold flat roof is one where the insulation is between or between and below the roof joists. The type that is right for your flat roof insulation job depends upon the state of the roof expert opinion on the best type and your budget.